Mitsubishi 380. Manual — part 715

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-270

STEP 34. Check the A/T- ECU for short circuit. Measure the
resistance at A/T- ECU connector B-19.

NOTE: When diagnosing CAN-BUS on vehicles with
manual transmission (M/T), disregard A/T-ECU and it’s wir-
ing circuits and measure between ABS-ECU and
ENGINE-ECU only.

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

CAUTION

A digital multimeter should be used. For details refer to

P.54C-4

.

(1) Disconnect A/T- ECU connector B-19, and measure the

resistance at the component side of A/T- ECU connector
B-19.

(2) Measure the resistance between A/T- ECU connector

terminals 13 and 14.

OK: 1 k

Ω or more

Q: Does the resistance measure 1 k

Ω or more?

YES : If the resistance measures 1 k

Ω or more, go to Step

35 .

NO : If the resistance measures less than 1 k

Ω, replace the

A/T-ECU.

16DB480A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

A/T

CONTROL

UNIT

16DB502A

HARNESS SIDE: B-19

TEST
HARNESS

TEST
HARNESS

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-271

STEP 35. Check the ENGINE- ECU for short circuit.
Measure the resistance at ENGINE- ECU connector B-21.

NOTE: When diagnosing CAN-BUS on vehicles with
manual transmission (M/T), disregard A/T-ECU and it’s wir-
ing circuits and measure between ABS-ECU and
ENGINE-ECU only.

CAUTION

A digital multimeter should be used. For details refer to

P.54C-4

.

(1) Disconnect ENGINE- ECU connector B-21, and measure

the resistance at the component side of ENGINE- ECU
connector B-21.

(2) Measure the resistance between ENGINE- ECU connector

terminals 64 and 86.

OK: 120

± 20 Ω

Q: Does the resistance measure 120

± 20 Ω?

YES : If the resistance measures 120

± 20 Ω, diagnose CAN

bus lines thoroughly by referring to

P.54C-323

.

NO : If the resistance does not measure 120

± 20 Ω,

replace the ENGINE- ECU.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB503A

HARNESS SIDE: B-21

TEST
HARNESS

TEST
HARNESS

NEXT PAGE

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-273

54C

DIAGNOSTIC ITEM 6: Diagnose terminator resistors at both ends

NOTE: When diagnosing CAN-BUS on vehicles
with manual transmission (M/T), disregard
A/T-ECU and it’s wiring circuits and measure
between ABS-ECU and ENGINE-ECU only.

CAUTION

When servicing a CAN bus line, ground yourself
by touching a metal object such as an unpainted
water pipe. If you fail to do so, a component con-
nected to the CAN bus line may be damaged.

.

16DB402A

A-02 (GR)

CONNECTOR: A-02

A-02 HARNESS CONNECTOR:

16DB407A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

A/T

CONTROL

UNIT

16DB505A

C-101

C-29

C-02

CONNECTORS: C-02, C-29, C-101

PREVIOUS PAGE

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-274

TROUBLE JUDGMENT

The terminator resistors at both ends of CAN bus
lines may be damaged, when the resistance
between the CAN bus lines (CAN_L and H lines) is
more than 2 ohms.

.

COMMENTS ON TROUBLE SYMPTOM

The CAN bus line harness wires or connectors may
be damaged (open circuit may be present on CAN_L
or CAN_H line between the data link connector and
CAN main bus lines, or CAN main bus lines may be
open at both sides), or the combination meter and
the ENGINE-ECU may be defective.

.

TROUBLESHOOTING HINTS

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• The wiring harness or connectors may have

loose, corroded, or damage terminals, or termi-
nals pushed back in the connector

• The combination meter may be defective

• The ABS-ECU may be defective

• The A/T-ECU may be defective

• The ENGINE-ECU may be defective

NOTE: When diagnosing CAN-BUS on vehi-

cles with manual transmission (M/T), disregard
A/T-ECU and it’s wiring circuits and measure
between ABS-ECU and ENGINE-ECU only.